Computer system, storage and storage utilization and monitoring method

ABSTRACT

A computer system includes a plurality of computers and at least one storage connected to the plurality of computers. The storage includes a device that obtains information concerning areas within the storage that are used by the respective plurality of computers, a device that obtains information concerning a capacity within each of the areas that is used by each of the plurality of computers to store data, and a device that notifies at least one of the plurality of computers of a status of the areas within the at least one storage. The computer system utilizes and manage the storage, without having each of the computers utilize and manage the storages with regard to storage capacity.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a computer system, a storage apparatusand a storage apparatus utilization and monitoring method, and moreparticularly to a computer system connected with at least a storageapparatus, and a storage apparatus (hereafter also referred to as“storage”), as well as a storage utilization monitoring method, in whichthe storage itself can utilize and monitor the usage status of thestorage.

The amount of data in storage in computer systems that corporationsutilize and manage has been increasing in recent years, which has causedthe utilization and management of storage to become more complex andincreased the costs for such utilization and management. One way tosolve this problem is to have the utilization of storage in the computersystems of corporations handled by vendors called storage serviceproviders (SSP), who utilize and manage storage for their clients.

An SSP is a business that has a plurality of storages and divides thestorages to provide them to a plurality of users. Users who let an SSPutilize the storage and entrust their data with the SSP can reduce thecost of utilizing and managing their data (see “SSPs That SupportService Enterprises.” Nikkei System Provider 16 Mar. 2001).

As part of the SSP's services, utilizing and monitoring the usage statusof the users' storages are useful in taking over the utilization andmanagement of the storages for the users. In fact, utilizing andmonitoring the usage status of storage are functions necessary not onlyfor the SSP but in general, in order for a computer to operate normallywithin an area of storage allocated to that computer.

There is a known technology regarding monitoring of storage capacity aspart of usage status of storage. The technology involves automaticallymonitoring the used capacity of disks that comprise a storage, where acomputer that uses the storage automatically ascertains the usedcapacity on the disks, and when the used capacity exceeds apredetermined reference value a warning is given to an administrator ofthe computer via electronic mail. However, this technology entails theproblems described below.

In general, when a computer uses a storage, the method employed in usingthe storage is determined by a file system that the computer uses. Forthis reason, although the storage can obtain information concerningvolumes that the storage itself has created, it cannot ascertain how thecomputer is using the volumes. For example, the storage cannot ascertainhow much of the volume capacity the computer is using.

Although storages that actually have their own file systems, such as NAS(network attached storage), can ascertain information described above,due to the fact that the NAS must have network connections such asTCP/IP and requires file I/O in the network file system, it cannot workwith SCSI, fibre channel connections, or block I/O access.

In order to ascertain the capacity of storage used by the computer or auser in a storage that is compatible with SCSI, fibre channel storageconnections, or block I/O access, a function that allows the computer tomonitor the capacity of the storage must be adopted. However, thisrequires adopting a separate storage monitoring function into thecomputer in addition to the normal utilization of the computer, and thiscreates a load on the operations of the computer and increases load onthe user with regard to utilization and management.

In the meantime, due to the structure of the SSP, users who are clientsof SSPs tend not to want utilization and monitoring services that SSPsoffer for the reasons described above. On the SSP administrators' side,managing the computers themselves is not part of their business purposesand they tend to want to avoid an increase in the number of actualdevices they utilize and manage. As a result, both the users who are theclients of the SSPs and the SSP administrators tend not to want to havestorages utilized and managed through the use of utilization andmanagement functions in the computers themselves.

SUMMARY OF THE INVENTION

The present invention therefore relates to a computer system, a storage,and a storage utilization and management method that make it possible toutilize and manage storage, without having computers utilize and managestorage with regard to storage capacity.

In accordance with one embodiment of the present invention, a storageitself monitors the usage status of an area used by a computer, monitorsand retains read/write positions in the storage based on I/O datainformation from the computer, and thereby obtains the usage status ofthe area used by the computer.

In accordance with an embodiment of the present invention, in a computersystem having one or more computers and one or more storages connectedto those computers, the storage has a device that obtains informationconcerning an area of the storage that each computer uses, a device thatobtains information concerning the capacity of the area within its areathat each computer uses to actually store data, and a device for thestorage to notify the computer or the computer user of the status of thearea.

In addition, the storage also may have a device to create new areaswithin the storage when the used capacity of the area increases; adevice to notify, after creating new areas, the user who will use thenewly created areas of the fact that new areas have been created; and adevice to notify, when the areas available for creating new areas withinthe storage decrease as a result of an increase in the areas created,the user who administers the storage of the necessity of a new diskdevice within the storage in order to be able to create new areas.

By providing the storage with the devices described above, the need iseliminated for the computer itself to have a function to utilize andmanage the storage and any load on the computer used by the user usescan also be eliminated, according to the present invention. For theadministrator of the storage, the only actual device that he or she hasto manage is the storage, which allows him or her to manage intensivelythe usage status of the storage, which in turn reduces management costs.

Other features and advantages of the invention will be apparent from thefollowing detailed description, taken in conjunction with theaccompanying drawings that illustrate, by way of example, variousfeatures of embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram indicating the configuration of a computersystem in accordance with one embodiment of the present invention.

FIG. 2 shows a drawing illustrating an example of storage information.

FIG. 3 shows a flowchart illustrating processing operations that takeplace to monitor the used capacity of volumes within a storage.

FIG. 4 shows a table indicating the structure of a storage informationchange history table.

FIG. 5 shows a flowchart illustrating the processing operations thattake place to notify the user of information concerning data locations.

FIG. 6 shows a block diagram indicating a configuration of a computersystem according to another embodiment of the present invention.

FIG. 7 shows a flowchart illustrating a data obtaining procedureconcerning data access through sharing of volumes having different datamanagement methods.

PREFERRED EMBODIMENTS

A computer system, a storage and a storage utilization and managementmethod in accordance with embodiments of the present invention aredescribed below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of a computer systemaccording to one embodiment of the present invention, and FIG. 2 is adrawing that illustrates an example of storage information. In FIGS. 1and 2, 10 a-10 n are each a computer, 11 a-11 n are each a storage, 110is a management module, 111 is storage information, 112 is a datamanagement information obtaining function, 113 is a storage managementcontrol function, 114 is a communication function, 12 a-12 n are each avolume, 120 is a group of volumes, 130 is a communication path such as acable, 200 is a volume information table, 210 is a volume managementpolicy table, 220 is a storage capacity table, and 230 is a userinformation table.

The computer system according to the embodiment of the present inventionincludes a plurality of computers 10 a-10 n and a plurality of storages11 a-11 n connected by the cable 130. The plurality of storages 11 a-11n all may have the same configuration, and FIG. 1 shows the internalconfiguration only of the storage 11 a. By using the storage 11 a as arepresentative of the entire storages, its internal configuration willbe described.

The storage 11 a comprises the group of volumes 120 and the managementmodule 110 that manages and controls the storage 11 a and that cancommunicate with each of the computers 10 via the cable 130, whichconnects each computer 10 with the storage 11 a. The group of volumes120 is a set of volumes, each of which is the minimum unit of storageavailable to be provided to each of the computers 10 a-10 n in the areamanage by the storage 11 a, and it comprises a plurality of volumes 12a-12 n that accepts, via the cable 130, I/O requests from computersamong the computers 10 a-10 n that use the storage 11 a.

The management module 110 comprises the storage information 111 thatretains information concerning area available for use by each of thecomputers (not necessarily all) among the computers 10 a-10 n that usesthe group of volumes 120 and information concerning area actually usedby those computers 10; the data management information obtainingfunction 112, which is a function to obtain data management formats touse the volumes 12; the storage management control function 113, whichis a function to actually control the storage 11 a, such as setting thevolumes 12; and the communication function 114, which is a function toallow communication, via the cable 130, between the storage 11 a and thecomputers 10 a-10 n.

The communication function 114 may be conventional electronic mailfunctions. The data management information obtaining function 112 is afunction that, depending on the data management method (for example,FAT, NTFS) such as a file system that each computer 10 uses, is used toobtain data locations and locations on disks of data and files used byeach of the computers 10. The cable 130 can be a cable that uses a fibrechannel or Ethernet (a registered trademark), and may in some cases beseparate networks of fibre channel and Ethernet (a registeredtrademark). In the latter case, a plurality of communication devices maybe located on the computers 10 a-10 n and the storages 11 a-11 n,depending on the type of the cable.

Among the computers 10 a-10 n, besides computers 10 that actually usethe storages 11 a-11 n, there may be a computer that works inconjunction with the communication function 114 of the storage 11 a toobtain information concerning the storage 11 a, that does not use diskswithin the storage 11 a, and that register setting requests to thestorage 11 a (hereinafter called a “management terminal”). Further, thefunctions of the management terminal may be incorporated into thecomputers 10 that use the storages 11 a-11 n.

The computer system according to the embodiment of the present inventionthat is comprised as described above may be a computer system utilizedby a specific user or a computer system utilized by an SSP.

If the computer system shown in FIG. 1 is a computer system utilized byan SSP, the computers 10 a-10 n issue requests concerning the storagefrom clients and clients' servers to the SSP, and are also themanagement terminals of the clients who obtain information from thestorages 11, as well as the management terminals through which the SSPadministrator obtains storage information. Additionally in this case,the storages 11 a-11 n are storages provided to clients by the SSP witha price attached to the volumes 12 of each storage 11. Further, one ormore volumes 12 a-12 n becomes a unit of storage provided to the eachclient by the SSP.

The storage information 111 that the management module 110 hascomprises, as shown in FIG. 2, the volume information table 200, thevolume management policy table 210, the storage capacity table 220 andthe user information table 230. The storage information 111 is used toutilize and monitor the storage 11 on which the management module 110 isprovided.

The volume information table 200 is a table that manages informationconcerning the volumes 12 set within a storage (the storage 11 a in thiscase). The volume information table 200 stores, for each volume ID 201assigned to identify each volume 12 defined within the storage 11 a, acomputer name 202 for the computer 10 that uses the volume 12, a datamanagement method 203 in which the data management method used by thevolume 12 is registered, a capacity 204 of the volume 12 available foruse by the computer 10, and a used capacity 205 that the computer 10actually uses. Each of the values stored in the computer name 202 is anidentifier for each of the computers 10 a-10 n. The data managementmethod 203 is an identifier for the data management method, such as afile system, that each computer 10 uses. The data management informationobtaining function 112 refers to this value and obtains the status ofdata location on each computer 10. Here, for the sake of simplification,we will assume that each volume 12 is managed by one data managementmethod. It is possible to divide one volume 12 into a plurality ofpartitions by a plurality of different data management methods, and toutilize the volume 12 in that manner. If this were the case, for eachvolume 12, information for each partition should be managed under thesame headings as in the volume information table 200, so that the volumeID 201 heading becomes partition identifiers, and the capacity 204 andthe used capacity 205 become information for each partition.

The volume control policy table 210 stores a volume ID 211, which is thesame as the volume ID 201 described earlier; an addition warning policy212 that designates, depending on the volume usage status, whether togive a warning when the utilization rate of the volume 12 increases; anaddition policy 213 that designates whether to add volumes 12 dependingon the volume usage status; and a notification destination 214 thatdesignates the user that the communication function 114 notifiesconcerning warnings and additions. The volume management policy table210 is set by the user of each volume 12. Depending on the contents ofthese headings, the storage 11 a warns the appropriate user or adds thevolumes 12 for the appropriate user.

The storage capacity table 220 stores a storage capacity 221, which isthe capacity of each storage 11 that is actually available for use; amaximum storage capacity 222 that registers the maximum value of thestorage capacity available for use as a result of adding disks; awarning policy 223 that designates whether to give a warning when theused capacity 221 of the storage approaches the value of the maximumstorage capacity 222, i.e., when there is a high possibility that thedisks in the storage 11 a may become insufficient; and a notificationdestination 224 that designates the user that the communication function114 notifies concerning warnings. The notification destination 224 isdesignated by the administrator of the storage 11 a. When a storageadministrator is designated as a notification destination, the storageadministrator can be urged through warnings to add new disks to thestorage 11 a or to perform other designated tasks. The storage capacitytable 220 is used as information to determine when to add the volumes 12and when to warn the storage administrator of the possibility ofinsufficient storage capacity. The warning policy 223 and thenotification destination 224 are set by the storage administrator.

In the user information table 230 are stored a user name 231, which is aname of the user to whom the storage usage status is notified; and userinformation 232, which is information required for the communicationfunction 114 to notify the user of information from the storage 11 a. Ifthe communication function 114 uses electronic mail functions, anelectronic mail address is set in the user information 232, so that thecommunication function 114 can use the user information 232 to notifythe user of storage information.

FIG. 3 is a flowchart that describes the processing operations that takeplace to monitor the used capacity of one of the volumes 12 within thestorage 11 a. This processing is executed by the management module 110of the storage 11 a by using the functions and information that theformer has.

(1) When the management module 110 receives a request directed to thestorage 11 a from one of the computers 10, the data managementinformation obtaining function 112 gains information concerning thechange in the amount of used capacity of one of the volumes 12 inrelation to the request to use the storage 11 a from the computer 10. Inaddition, the data management information obtaining function 112 usesthe information in the data management method 203 of the volumeinformation table 200 to ascertain the used capacity of the volume 12,in accordance with the data management method of the volume 12 (step300).

(2) Based on the used capacity of the volume 12 as ascertained in theprocessing in step 300, the management module 110 recognizes that achange has occurred in the used capacity of the volume 12 that itmanages and makes changes through the volume information table 200 tothe used capacity 205 for the volume 12 having the volume ID that isused by the computer 10 that made the request (step 301).

(3) Next, the management module 110 uses the volume information table200 and the volume management policy table 210 to check whether the usedcapacity of the volume 12 matches the status designated by the warningpolicy 212. In other words, the management module 110 calculates thepercentage is of the capacity 204 available for use in the volumeinformation table 200 that the used capacity 205, which is the actualused capacity, is at; and the management module 110 checks whether thisvalue matches the status designated by the warning policy 212 of thevolume management policy table 210 (step 302).

(4) If as a result of checking in step 302, the status is found to bethe status designated by the warning policy 212, e.g., in FIG. 2, if theutilization rate of the volume 12 whose volume ID is 2 in the volumeinformation table 200 is found to be 95% upon calculation, which matchesthe status designated by the warning policy 212 of the volume managementpolicy table 210, the management module 110 uses the communicationfunction 114 to notify the user in the notification destination 214 ofthe volume management policy table 210 of the warning concerning theusage status of the storage 11 a (step 303).

(5) If as a result of checking in step 302 the status is found not to bethe status designated by the warning policy 212, or if after theprocessing in step 303 the used capacity of the volume 12 is checkedusing information in the volume information table 200 to see whether itsstatus is the status designated by the addition policy 213 of the volumeinformation table 200 and found not to be the status designated by theaddition policy 213, the processing is terminated in this step since noadditions are necessary yet (step 304).

(6) If as a result of checking in step 304, the status is found to bethe status designated by the addition policy 213, e.g., the utilizationrate of the volume 12 whose volume ID is 2 is 95% in the volumeinformation table 200, which matches the status designated by theaddition policy 213, whether an addition of a new volume 12 is possibleis checked next using the storage capacity table 220 (step 305).

(7) If as a result of checking in step 305, an addition cannot be made,the management module 110 uses the communication function 114 to notifythe user in the notification destination 214 of the volume managementpolicy table 210 of the fact that a new volume 12 cannot be added, andterminates the processing. When there is a storage administrator inaddition to the user, such as with SSPs, the notification that anaddition cannot be made can be sent to the administrator (step 307).

(8) If as a result of checking in step 305 an addition is possible,e.g., in FIG. 2, if the storage capacity 221 is 1T and the maximumstorage capacity is 2T in the storage capacity table 220, this indicatesthat 1T may be added to the existing storage configuration. In themeantime, if the volume 12 in question is the volume 12 whose volume IDis 2, the request from the addition policy 213 of the volume managementpolicy table 210 is a request for an addition of 100 GB, which isconsidered allowable, and the storage management control function 113therefore adds a volume 12 in accordance with the addition policy 213.The management module 110 uses the communication function 114 to notifythe user in the notification destination 214 of the volume managementpolicy table 210 of the fact that the volume 12 has been added.Furthermore, with the addition of the volume 12, the storage capacitytable 220 is updated. For example, if 100 GB were added in accordancewith the addition policy 213 for the volume 12 whose volume ID is 2, thevalue in the storage capacity 221 is updated to a value of 1 T plus 100GB. At the same time, an ID is assigned to the newly added volume 12 inthe volume information table 200 and the volume management policy table210, so that a new line is added to each of the tables, and an entry isadded to each of the volume information table 200 and the volumemanagement policy table 210 when setting the new volume 12 available foruse by the computer 10 (step 306).

(9) After completing the processing in step 306, the management module110 checks whether the status is the status designated by the warningpolicy 223 of the storage capacity table 220, and if the status is notthe status designated by the warning policy 223 the processing isterminated in this step. For example, if the value of the storagecapacity 221 is 1 T and the value of the maximum storage capacity 222 is2 T in the storage capacity table 220, the utilization rate is 50%,which does not satisfy the requirement for the warning policy 223, andthe processing is terminated (step 308).

(10) If as a result of checking in step 308, the status is found to bethe status designated by the warning policy 223, e.g., if the value ofthe maximum storage capacity 222 is 2 T and the value of the storagecapacity 221 is 1.9 T in the storage capacity table 220, the utilizationrate is 95%, which matches the status designated by the warning policy223; consequently, the management module 110 uses the communicationfunction 114 to notify the user in the notification destination 224 ofthe storage capacity table 220 of the warning concerning the status ofthe storage capacity (step 309).

The present embodiment according to the present invention makes itpossible for the storage 11 a itself to monitor the usage status of thestorage 11 a, to notify the user or the administrator, and toautomatically add new volumes 12, by having the processing describedabove executed in the storage 11 a itself, and without having to installmonitoring software on any of the computers 10. In addition, since theused area of the storage 11 a itself can be monitored at all times, thestorage administrator can respond flexibly to disk additions within thestorage 11 a depending on the usage status of the storage 11 a.

Furthermore, since the present embodiment according to the presentinvention allows an exchange of information between the user and thestorage 11 a without having to go through the administrator even whenthe storage 11 a is utilized by an SSP, the time it takes to makechanges to the storage setting can be shortened. When the storage isutilized in a manner that requires authorization in relation to storagesettings, i.e., when no one other than the storage administrator isallowed to set or change the storage settings, the notification betweenthe storage 11 a and the user described above can be made via thestorage administrator.

When adding a new volume 12 in the processing in step 306, if thecomputer 10 that is to use the new volume 12 has a volume expansionfunction, an existing volume 12 with an existing volume ID may beexpanded in the storage 11 a.

By utilizing an SSP in the manner described above, the need to provideextra software to the computers 10 of the SSP's clients is eliminated,and the volume usage status of the SSP's clients can be ascertained bythe utilization of the storage 11 a. The SSP administrator can at anytime monitor the SSP clients' volume usage status through theutilization of the storage 11 a, which would allow the administrator togive warnings early and to automatically add new volumes 12; as aresult, the SSP can provide to its clients services that are equivalentto services that clients would have if software that monitors the usagestatus of the storage 11 a were installed on the clients' computers.From the SSP clients' perspective, this arrangement does not create anynew load on their computers since the clients do not have to installextra software.

In accordance with the embodiment of the present invention, a setting,used to notify the storage administrator (or the SSP administrator) ofany changes to any of the values in any of the tables in the storageinformation 111 whenever a change is made, can be included in thestorage information 111. By doing this, the storage administrator cancomprehensively ascertain changes to the usage status of the entirestorage 11 a. Further, by installing on the storage 11 a software thatcomprehensively displays the information provided from the storage 11 ato the administrator, the administrator can realize more reduction inthe management cost.

In accordance with the embodiment of the present invention, themanagement module 110 can be provided with a function to separatelyretain each of the tables in the storage information 111 periodically ora whenever a change is made to any of the tables, which makes itpossible to ascertain the volume usage status for each period. Based onthis information, the management module 110 can provide the user withthe volume usage status, which can be used by the user to make his orher decision regarding his or her use of the volumes 12.

FIG. 4 is a table showing the structure of a storage information changehistory table. This table manages information retained for each of thetables managed by the storage information 111 when the tables areseparately retained periodically or whenever a change is made to any ofthe tables.

The storage information change history table 400 shown in FIG. 4comprises time 401, which is the time at which a table in the storageinformation 111 was retained; a table type 402, which is the type oftable in the storage information 111; and a table name 403, which is thename of the table that was retained. By referring to the table 400, itis possible to determine that storage information 111 was retained atthe time indicated in the time 401. For example, if each of the tablesin the storage information 111 is retained periodically (for example,every hour), it becomes possible to notify the user of the volume usagestatus on an hourly basis and the user can check the volume usage statusin a chronological order.

Or, for example, when there is a change made to the content of thestorage information 111, a change history of the volumes 12 can beobtained since the tables are separately retained, and the user can benotified of the trend in the volume usage status by providing thisinformation to the user. Users whose utilization rate of the storage 11a has not increased can be urged to change volume settings. By doingthis, the operational rate of the storage 11 a can be increased, so thatthe storage 11 a can be used efficiently.

In other words, if a plurality of users is each using a separate volume12, the usage status of each user can be found from the content of thestorage information change history table 400; users who are hardly usingtheir volumes 12 can be urged to reduce the amount of the volumes 12they have, and once the amount of their volumes 12 is reduced, newvolumes 12 can be added for other users; in this way the storageresources can be used efficiently. If the storage is utilized by an SSP,the SSP can urge its clients to add or reduce their volumes 12 by aflexible pricing of such additions and reductions of the volumes 12.

If data locations within the volumes 12 are obtained and the datalocations are found to be fragmented, the embodiment of presentinvention can notify the user of it and urge the user to optimize thedata locations. The processing operations that take place in such asituation will be described next.

FIG. 5 is a flowchart that describes the processing operations to notifythe user of information concerning data locations.

(1) First, the data monitoring processing that monitors the usedcapacity of the volumes 12, which was described using FIG. 3, isexecuted. By performing this monitoring processing, an opportunity tonotify the user of information concerning data locations can be providedevery time there is an access to the storage 11 (step 500).

(2) Next, the relations between the data locations and disk locationswithin the storage 11 are obtained. For example, information concerninghow consistent data (for example, one file) is located among variousdisks of the storage 11 is obtained. This processing is executed by thedata management information obtaining function 112 that obtains thelocations of a series of data in each of the volumes 12 in each of thestorages 11. For example, the locations of each data in the group ofvolumes 120 of the storage 11 a are obtained. Further, the diskconfiguration of each storage 11 is obtained from the storage managementcontrol 113 and where on the disks each data is located is retained. Bydoing this, the relations between the data locations and the disks canbe obtained (step 501).

(3) Next, whether the data is fragmented is determined based on therelations between the data locations and the disks that were obtained instep 501. For example, when a file is located on disk 1 and disk 2, thisdata is determined to be fragmented. If there are no fragmented data,the processing is terminated without any further steps (step 502).

(4) If in step 502 there is data that is determined to be fragmented,the communication function 114 is used to notify the fact that the datais fragmented to the user, who is designated to be notified of thestatus of the relevant volume 12, and the processing is terminated. Theuser to be notified can be obtained from the value of the notificationdestination 214 of the volume management policy table 210 and from theuser information table 230 that retains information concerning thenotification destination user (step 503).

By providing step 500, a processing is activated to notify the user ofthe information concerning data locations every time there is an accessto the storages 11, but if the accesses are made frequently thisprocessing will be activated many times, which can increase processingload on the storages 11 themselves. In consideration of such asituation, a means to activate the processing to periodically notify theuser of information concerning data locations can be provided in thepresent invention, so that the processing begins with step 501.

Additionally, in the processing that takes place in step 503, if thedata that is fragmented has fewer changes than other data, a processingto notify or not notify the user of this can be provided in step 503.Changes to data can be determined from the storage information changehistory table 400 for the storage information 111, which was describedusing FIG. 4.

In the present embodiment according to the present invention, byperforming the processing as described above, each of the storages 11itself can monitor the data locations and notify the user if itdetermines that the processing by the storage 11 would become slow dueto the data locations, without having the computer monitor the datalocations. Upon receiving the notice, the user can automatically obtaininformation from the storage 11 that the user can use to optimize thedata locations.

If the storage 11 is utilized by an SSP, the storage 11 can still beutilized in the manner described and provide the monitoring servicesdescribed; consequently, the SSP administrator can, without having toprovide extra software on the clients' computers, monitor the datalocations at all times through the utilization of the storage 11 andgive warnings if any data is found to be fragmented. From the SSPclients' perspective, this arrangement does not create any new load ontheir computers since they do not have to install extra software.

FIG. 6 is a block diagram indicating the configuration of a computersystem in accordance with another embodiment of the present invention,and FIG. 7 is a flowchart illustrating a data obtaining procedureconcerning data accesses performed when volumes 12 having different datamanagement methods are shared. The embodiment of the present inventionshown in FIG. 6 is an example that makes it possible for a plurality ofcomputers 10 having different data management methods to share thevolumes 12 and to operate data. In FIG. 6, 600 is a data conversionfunction, and other numbers are identical to those in FIG. 1.

The computer system in FIG. 6 includes the data conversion function 600provided in a management module 110 within a storage 11 a of a computersystem in FIG. 1, and computer system in FIG. 6 is identical to thecomputer system in FIG. 1 in other respects. By providing the dataconversion function 600, it becomes possible for the plurality ofcomputers 10 to obtain data in the volumes 12 having different datamanagement methods. The data conversion function 600 may be providedwith a function to manage all access rights to the volumes 12 by eachcomputer 10. Through this, unauthorized accesses to the volumes 12 canbe blocked.

Next, referring to the flowchart in FIG. 7, descriptions are made as tothe data obtaining procedure concerning data accesses performed when thevolumes 12 having different data management methods are shared. Thisprocessing is executed by the management module 110 provided in each ofthe storages 11.

(1) When one of the storages 11 receives an I/O request from one of thecomputers 10, the management module 110 determines which of the volumes12 the I/O request's access is for (steps 700 and 701).

(2) Next, the management module 110 determines whether the datamanagement method currently designated for the volume 12 to be accessedis different from the actual data management method. This determinationcan be made using the information in a volume information table 200. Forexample, if a computer A and a computer B share the volume 12, whosevolume ID is 2, of the computer B, it is possible to determine from thevolume information table 200 that the data management methods of thecomputer A and the computer B are different (step 702).

(3) If the determination in step 702 shows that the data managementmethods are not different, the processing is terminated without anyfurther steps. In this case, since the data management methods are thesame, data can be obtained by the data management information obtainingfunction 112 using the same data management method.

(4) If the determination in step 702 shows that the data managementmethods are different and that data conversion is required, the dataconversion is performed using the data conversion function 600. Forexample, in FIG. 2, since the information from a data management method203 shows that the data management method for the computer A is “1,”while the data management method for the computer B is “2,” an accesswith the data management method “1” from the computer A is converted toan access with the data management method “2.” In this way, data in thevolume 12 whose volume ID is 2 and that is managed by the computer B canbe obtained from the computer A as well. Consequently, once thisprocessing is completed, the computer A can obtain the computer B'sdata, which is data in the data management method “2,” as data whosedata management method is “1” (step 703).

Through the processing described in FIG. 7, data managed under differentdata management methods can be shared and different computers 10 canobtain the data, without having to use data sharing software on thecomputers 10.

When the storage 11 is managed by an SSP, the SSP can provide a datasharing service by having the storage 11 perform the processingdescribed above, without using storages such as NAS with a file serverconnected on a network, and even if the access method is a block I/Osuch as in fibre channel and SCSI connection.

Various processing in the embodiments according to the present inventioncan be configured as a processing program, and such a processing programcan be stored and provided in recording medium such as HD, DAT, FD, MO,DVD-ROM and CD-ROM.

According to the embodiment of the present invention, the managementmodule 110 within each of the storages 11 can at all times monitor theusage status of the volumes 12 used by the computers 10 and have thestorage 11 notify the user depending on the changes in the usage status,which makes it possible to notify the user of the usage status of thestorage 11 without having to install monitoring software on the computeror server that the user uses.

Further in accordance with the embodiment of the present invention, dueto the fact that the data conversion function for the volumes 12 isprovided in the management module 110 of each of the storages 11, aplurality of computers 10 can obtain data in various volumes 12, even ifthe data management methods of the various computers 10 are different,without having to install data conversion software on the computers 10.

According to the present invention, the utilization and management ofstorage can be done without having the computer perform the utilizationand management of storage with regard to storage capacity, as describedabove.

While the description above refers to particular embodiments of thepresent invention, it will be understood that many modifications may bemade without departing from the spirit thereof. The accompanying claimsare intended to cover such modifications as would fall within the truescope and spirit of the present invention.

The presently disclosed embodiments are therefore to be considered inall respects as illustrative and not restrictive, the scope of theinvention being indicated by the appended claims, rather than theforegoing description, and all changes which come within the meaning andrange of equivalency of the claims are therefore intended to be embracedtherein.

1-21. (canceled)
 22. A storage to be coupled to at least one ofcomputers via a network, comprising: a storage controller to communicatewith the computers via a network; and, a first volume and a secondvolume which are connected to the storage controller and which areprovided, to store data, with the host computer; wherein the firstvolume is allocated to the first computer and is managed by a first userand the second volume is allocated to the second computer and is managedby a second user; when an used capacity of the first volume is exceed ina first predetermined capacity, the storage controller checks an usedcapacity of the second volume and sends, to the second user via anetwork, a notification for reducing unused capacity of the secondvolume to the second user on the basis of results of check.